Neon Tetra Discoloration

[KidGloves]

Hello all,

I noticed a pale mark near the dorsal fin on a neon tetra (see photos below) several days ago. My first thought was columnaris or neon tetra disease so I quarantined him; however since he acts normal I'm wondering if the mark is an injury I hadn't noticed before. Any thoughts on what the mark is?

Tank size: 20 gallons
pH: 6.4
ammonia: 1-2 ppm
nitrite: 0.0-0.25 ppm
nitrate: 10-20 ppm
kH: not measured
gH: 64 ppm
tank temp: 78F

Fish Symptoms: The only visible symptom is the mark near the dorsal fin. The tetra has been eating and schooling with the other tetras as normal. I've had this tetra for a little over 3 months; he's grown considerably since the time of purchase and has seemed healthy until now. I have lost one zebra danio and one neon tetra in the last six months. I thought that the losses were age related since I purchased them over two years ago but maybe it's something else.

Volume and Frequency of water changes: 20% (~4 gallons) weekly (+/- 2 days)

Chemical Additives or Media in your tank: Aqueon water conditioner

Tank inhabitants: 4 other neon tetras, 3 zebra danios, 6 small (<1/2") black mystery snails, 6 marimo moss balls

Recent additions to your tank: The most recent additions were two neon tetras (including the one with the mark) 3 months ago.

 

[TropicalBarnacle]

Hello- I know this is an old thread but what ended up happening to you neon? I just brought home a school of 6 yesterday and noticed one of them with a similar spot today. It could have been there already yesterday but I didn't notice

 

[10 Tanks]

Hello. 99.9 percent of tank problems are water related. It's really that simple. If you have traces of ammonia and nitrite in the tank water, you're not changing enough water and you're not changing it often enough. Fish live in a well planted and beautifully aquascaped toilet. This is because they must live in the same water container where they do all their "business". I've said this before and I'll say it again. Tanks up to 30 gallons need half the water changed a couple of times a week. Tanks 30 gallons and larger need half the water changed weekly. If you're not doing this, then you're putting your fishes' health at risk.

10 Tanks (Now 11)

 

[TropicalBarnacle]

Hello. 99.9 percent of tank problems are water related. It's really that simple. If you have traces of ammonia and nitrite in the tank water, you're not changing enough water and you're not changing it often enough. Fish live in a well planted and beautifully aquascaped toilet. This is because they must live in the same water container where they do all their "business". I've said this before and I'll say it again. Tanks up to 30 gallons need half the water changed a couple of times a week. Tanks 30 gallons and larger need half the water changed weekly. If you're not doing this, then you're putting your fishes' health at risk.

10 Tanks (Now 11)

Thanks. I have a 50 gallon recently cycled tank and have been testing the parameters daily. Previously had 6 neon tetras which have been thriving, and decided to add 6 more.

Ph 7.5
Ammonia 0
Nitrite 0
Nitrate 10 ppm

 

[10 Tanks]

Thanks. I have a 50 gallon recently cycled tank and have been testing the parameters daily. Previously had 6 neon tetras which have been thriving, and decided to add 6 more.

Ph 7.5
Ammonia 0
Nitrite 0
Nitrate 10 ppm

Hello again. The reason your fish are healthy is simple. You have just a few small fish in a considerable amount of tank water. The waste of such a small number of fish is easily diluted to a safe level in all that 50 gallons of water. However, waste material in a large tank can still build up. So, to maintain suitable water conditions, you'll still need to remove and replace half the water every week. No excuses! Healthy water conditions isn't only about removing dissolved waste material. It's also necessary to remove and replace the water to maintain a steady level of all the chemicals that make up the water.

10 Tanks (Now 11)

 

[TropicalBarnacle]

Thanks 10 Tanks. I am not new to the hobby...just new for this tank so I understand the importance of water changes. However, my original question regarding the discoloration is still outstanding. Does this look like "neon tetra disease"? I am trying to catch this one so I can isolate him but I have been struggling with that. Thanks so much for your feedback.

 

[10 Tanks]

Thanks 10 Tanks. I am not new to the hobby...just new for this tank so I understand the importance of water changes. However, my original question regarding the discoloration is still outstanding. Does this look like "neon tetra disease"? I am trying to catch this one so I can isolate him but I have been struggling with that. Thanks so much for your feedback.

Hello again. If I have what may be a sick fish, I add a couple of duties to my tank maintenance routine. Once I keep the water cleaner with a bit more aggressive water change routine, I start adding a bit of standard aquarium salt to the new, treated tap water. A tablespoon in every four to five gallons of tank water I remove. If I believe there's some sort of pathogen responsible for my fish's condition, a trace of salt in the water can kill it. I also do a thorough job of vacuuming the bottom material. At this point I'm more concerned about all my healthy fish, than the one that appears sick.

10 Tanks (Now 11)

 

[Colin_T]

The fish in the picture appears to have a bacterial infection, which doesn't look like neon disease. It could be a localised infection or something growing under the skin. You could try salt or a broad spectrum medication that treats bacteria, and if that doesn't work then antibiotics. If the patch spreads rapidly and other neons get it, then it's neon disease or Columnaris, both of which need antibiotics.

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SALT
You can add rock salt (often sold as aquarium salt), swimming pool salt, or any non iodised salt (sodium chloride) to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres (5 gallons) of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, Bettas & gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria, fish, plants, shrimp or snails.

After you use salt and the fish have recovered, you do a 10% water change each day for a week using only fresh water that has been dechlorinated. Then do a 20% water change each day for a week. Then you can do bigger water changes after that. This dilutes the salt out of the tank slowly so it doesn't harm the fish.

If you do water changes while using salt, you need to treat the new water with salt before adding it to the tank. This will keep the salt level stable in the tank and minimise stress on the fish.

When you first add salt, add the salt to a small bucket of tank water and dissolve the salt. Then slowly pour the salt water into the tank near the filter outlet. Add the salt over a couple of minutes.